A stroke occurs when the blood supply to a part of the brain is suddenly disrupted or cut off, starving the brain cells of vital oxygen and nutrients, and causing severe damage in the area affected. Around 100,000 people suffer a stroke in the UK every year, and stroke is the fourth biggest killer in the UK, with almost 38,000 dying in 2016 (Stroke Association, 2018). 

Stroke is also a major cause of disability: around two-thirds of people who survive the condition leave hospital with an impairment. This can include problems with speech and language, loss of bladder and bowel control, and weakness in the arms and legs. As many as 60% of stroke survivors also suffer visual problems immediately afterwards (Stroke Association, 2018). 

Most visual problems that can happen after a stroke are divided into four main areas, says Fiona Rowe, Professor of Orthoptics at the University of Liverpool: “They can have impaired central vision, which includes reduced visual acuity, contrast and colour. Another issue is eye movement problems, such as nerve palsies, leading to incomitant squints. Then there is visual field loss. The final category is that of visual perception, which includes visual neglect or inattention, and other agnosias in which objects are seen but not recognised. All in all, it is a wide spectrum of disorders.”